The goal of these studies is to identify host cell functions that are necessary for the replication of oncogenic viruses. We will utilize temperature sensitive hamster cell mutants to determine if cellular alterations which prevent cell growth also prevent virus multiplication. Thus a temperature sensitive cell which allows virus replication at 33 degrees but not at 39 degrees is temperature sensitive for virus replication as well as for cell growth. The role of the altered cellular function will be identified by characterizing the incomplete virus replication at 39 degrees. Thus it will be possible to demonstrate the obligatory participation of cellular components in virus replication. The virus to be utilized will be adenovirus 2, a DNA tumor virus which replicates in the hamster BHK-21 cell line. BIBLIOGRAPHIC REFERENCE: Nishimoto, T., Raskas, H.J., and Basilico, C.: Temperature sensitive cell mutations which inhibit adenovirus 2 replication. Proc. Natl. Acad. Sci. 72: 328, 1975.